Interlock for elevators



M. J. ROBERTSON INTERLOCK FOR ELEVTORS Filed Aug. 30, 1926 3 Shoets-Sheet 1 avweuto m m W Dec. 18, 1928.

M. J. ROBERTSON n INTERLOCK FOR ELEVATORS 3 Sheets-Sheet 2 Filed Aug. 30. 1926 Dec` 18, 1928.

M. J. ROBERTSON INTERLOCK FOR ELEVATORS Filed Aug. 30, 1926 3 Shouts-sheet 3 %2 2% alma/%w Patented Dec. 18, 1928.

UNITED STATES.

w w 1,69s,469

PATENT OFFICE.

MARTIN J. BOBERTSN, oF LoUIsvILLn, KENTUCKY, Assrevon ro AMERICA ELE- VATOR AND MAVCHINE co., OF LOUISVILLE, KENTUCKY.

INTERLOCK FOR ELEVATORS( Application filed August 30; 1926. Serial No. 132564.

This invention relates to an interlock for elevators and while it is especially designed for use in automatically controlled elevators operated by the public, it `can also be used to advantage with any electric elevator.

It is an object of the present invention to provide a means whereby the door of an elevator enclosure cannot be opened While the car is in motion and a further object is to prevent the starting of the elevator car while any of the doors of the enclosure are open.

It is well known to those skilled in theart v that while some devices have been provided tor the purpose of preventingoperation of the doors of an elevator enclosure While the elevator car is in motion, such devices have been obj ectionable because it has been found, by exerting a. constant pull upon adoor in an efi'ort to open it, said door will open' the instant the elevator car passes the particular door; This has resulted in serious accidents which it is an object of the present invention to avoid.

lVith the foregoing and other objects in View which will appear as the description proceeds, the invention resides in the com- `bination and arrangement of parts and in the details of Construction hereinafter described and claimed, it being 'understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope of what is claimed without departing from the spirit of theinvention.

In the `accompanying drawings, 'the preferred form of the invention has been shown.

In said drawings, t

Figure 1 is a. front elevation of the lock with the cover removed and the magnet being shown in section and a door locked in closed position. i

Figure 2 is a similar View showing the door unlocked; r i

Figure 3 is a side elevation of the structure,

portions of the doors being shown in section V and a part of the housing of the structure being broken away.

Figure 4 is a diagram showing the wiring of the apparatus. 4 r V Referring to the figures by characters of reference 1 designates a. part of the elevator enclosure provided with the usual or any prev ferred forms of doors-2 for use' at the diflereut landings. To each door is connected a bracket &depending therefrom and carrying a laterally extending tongue 4 constituting a keeper This tongue is provided in' the upperedge of its freeendporton With ratchet teeth 5 while within the lower portion of its free end below the teeth is an inclined slot The elevator car, a portionof which has been ndcated at 7, is provided with an upwarclly extending deflectingarm 8 constituti ing a cam. i

Secured to the wall of the enclosure adacentthe path of the camS is a housing 9 having an opening 10 in one wall thereof for the reception of the keeper 4 when the door 2 is closed as shown, for example, in Figure 1. A pivot pin 11 is arranged within the housing 9 and has a pawl 12 mounted thereon with its head 13 so located as to engage one` of the teeth 5 When the keeper is inserted into the'housing 9. The' pawl has ajdepending arm l4 adapted to receive thrust from a spring '15 nterposed between said arm and e one arm 16 of a lever 17 pivotally mounted on'the pin 11. The other arm of this lever has a laterally extending hearing pin 18 adapted to work within a. slot 19 in the housing 9 and the outer end portion of this pin has a wheel 20 journaled upon it.- A spring 21 thrus'ts against lever 17 so as to hold the pin 18 normally at one end of the slot` with the head 13 of the pawl l2 in its lowermost position and upwardmovement of the pawl 12 relative tothe lever is limited by a stop finger 22 earred by the pawl and adapted to against the'lever 17,' as shown.

An electromagnet 23- is arranged in the housing and has an armature 24 :from which is extended a pin 25 adapted to bear upon the pawl 12. This magnet is of sufficient strength to overcome the resistance of the spring 15.

A switch lever %is fulcrumed in the housing' 9 andhas a pin 27`extending from one end thereof slidably engaged by a contact plate 28; A spring 29 is mounted on this pin and bears against the plate. Separate contacts'SO suitably insulated from each other are arr'anged within. the housing and are so located that when the lever 26 is moved in one direction the plate 28 will come against both Contacts and connect them electrically.

;One end portion'of the lever 26 has a lat-' erally extending roller 31 adapted to bere- -ceived by the slot 6 in keeper 4 so that when the keeper is moved to the position shown, for

example, in Figure 1, the roller 30jwillbe bear shifted by the walls of the slot 6 so as to cause the lever 26to move plate 28 to circuit closing position.

In Figure 4 the wiring of the invention has been illustrated in diagram. The motor for Operating the elevator car has been indicated at 32, the control panel has been indi cated at 33 and the switch on the eleva'tor car has been indicated at 34. Lock housings at two of the landings of the elevatorshaft have been: shown at 9. All of the contacts 30 are arranged in series with' the inovable switch element 35 carried by the car and t'orming a part of the car switch Bet so that the circuit is broken unless the plates 28 at all landin s are in engagement with their Contacts. This is only possible, of course, when all of the doors are closed. The leads or service wires have been indicated at 36 and 37. Separate magnetic switches are provided asindicated at 38 and 39, each switch being a doubled switch adapted, when closed, to complete a circuit through the motor as will be obvious. When one switch is closed, however, the current flows in one direction through the motor whereas when the other switch is closed the direction of flow of the current is reversed. Thus the motor can be operated to move the elevator car upwardly or downwardly.

The coil of the magnetic switch 38 electrically connected to the lead 37 and to one contact 4:1 of the car switch. The other contact 42 of the car switch is eleetrically connected to the coil of the other magnetic switch, said coil being indicated at 43 and being electrically connected to the lead 37.

The magnetic switches are normally open. It willbe apparent, however, that when the switch element 35 is shifted to engagemont with the contact 41 a circuitswill be completed from the lead 37 through coil 40 and thence through the contacts 30 and the plates 28 back to the other leads 36. The energizing of the magnetic switch will cause a circuit to be completed through said switch 38 to the motor 32 so that the elevator car can thus be caused to move in one direction. By sliiting the switch elenent 35 to engagement with the other contact 42 the other magnetie switch will beioperated to drive the motor in the opposite direction. Obviously, however, the motor cannot be operated unless all of the doors are closed because it is essential that the circuit be completed between the con- 'tacts 30 and thisisonly possible when the plates 2-8 are in engagement with the contacts 30 at all of the landngs. a

When the circuit `is closed to the motor through the car switch the elevator car will travel in the selected direction and as it passes each landing a cam rail 8 novable with the `car comes against the roller 20 at said landingand thrusts it laterally as indicated by broken lines in Figure 2. As long as the current is fiowing to the motor and the car is in motion, however, the magnet 23 remains energized as will be apparent and, thei-etore, the pawl 12 will be held against disengagement from the teeth 5. In other words the pawl will be retained in the position shown in Figure 1 although the'wheel 20 can be thrust laterally by the cani rail against the action of the spring 21. Consequently the door remains locked and cannot be opened. It', however, the elevator car is brought to a stop at any particular landing the magnet 23 will bedc-energized as soon as the current to the motor is cut off and, theret'orethe spring 15, which has been placed under compression by the lateral Shlfting of wheel 20 relative to the pawl 12, as shown by broken lines in Figure 1, will promptly thrust against the arm 14 of the pawl 12 and cause the pawl to swing up` wardly and release the tongue 4; The door at this landing can therefore be opened and the weight 45 provided at the upper end ot the lever 26 will gravitate to break the connection at the Contacts 30 as shown in Figure 2. Obviously it is now impossible to start the motor. However When the door is closed the recessed portion 6 of the tongue 4 comes against the' roller 31 and swings the switch lever 36 so as to bring plate 28 against the Contacts 30. At the same time the teeth 5 are brought to position underthepawl. When the car switch is closed so as to direct current to the motor, magnet 23 is pi'onptly energized with the result that pin 25 will be thrust against the pawl 12 and force it into engagement with the toothed tongue and there hold it so that the tongue cannot be wthdrawn. This positionwill be maintained as long as the magnet is energized and irrespective of the movement of cam rail 8 into contact. with successive wheels 20 atthedifi terent floors or landings. If, at any time, a door should be left open at any point along the elevator shatt, it would not oe possible to start the motor because the circuit would be broken at the Contacts 30 as shown in Figure 2. It is necessary that all of the doors be closed before the car can be operated and it is necessary 'or a car to be at. a selected landing and the currentcut off before'the door at that particular landing can be opened. The doors at the other landings cannot be opened when the car is remote therefroni because the springs 21 holdthe pawls [2 tightly in engagement with the ,teeth 5 of the tongues.

What is 'claimed is: I V

1. The `combination with an elevatorcar and an enclosure therefor having a door, of an electric motor for actuating the car, a switch adjacent the door for controlling the operation of the motor to bring the car to said door, a lock for fastening the door When lon llU

partly or entirely closed, means' controlled by the flow of current to the motor for holding the lock against release of the door while the car 'is passing the door, means tor releasing the locked doors upon failure of current, and cooperating means on the' car and lock for positively unlocking the door 'when the car is at rest at the door with the motor circuit open.

2. The combination 'with anelevator car and an enclosure thereior having a plurality of doors, of an electric motor for actuating the car, a lock for fastening each door when 'partly or entirely closed, a switch adjacent each door for controlling the operation of the motor to bring the car to'said door, a'motor controlling switch on the car, means controlled by the flow of current to the motor 'for holding all of the locks against release of the doors while the car is passing the doors, co- Operating means on the car and lock for positively unlocking any one of the doors-when the'car is at rest at said door with the motor circut open and means for 'releasing the locked doors upon 'failure of current.

3. The combination with an elevator car, an enclosure door, an electric motor for actuating the car, of a magnetic switch remote from the car for controlling the flow of current to the motor, said switch being normally open, a car switch for closing the circut to the magnetic switch to actuate the same, a lock for fastening the door when partly or entirely closed, a circut closer constituting a partof the lock and included in the circut with the car switch, cooperating means upon thedoor and the lock formaintaining the circuit closer in position to hold the circut close to the car switch while the door is closed, said means cooperating to'break the circuit when the door is opened, and electrically operated means 'or holding the door looking means in engagement with each other during the flow of current to the motor.

4. The combination with an elevator car, an enclosure door, an electric motor for actuating the car, of a magnetic switch remote from the car for controlling the flow of eurrent to the motor, said switch being normally open, a car switch for closing the circut to the magnetic switch to actuate' the same, a circut closer included n the circut with the car switch, a lock casing adjacent the door, cooperating means upon the door and in the lock casing for maintaining the circut closer in position to hold the circut closed to-the car switch while the door' is closed, said means cooperating positively to break the circut 'when the door sopened, cooperating means upon the door and lock for positively fastening the door in partly or entirely closed position,electrica1ly operated means for holding the door looking means in engagement with each other during the flow of current to the motor, and cooperatingmeans upon the car and lock forautomatically unlocking' the door when the car is at the door and the current to'the motor is cut ot.

5. A lock, for el vator doors including a housing, a member having a longitudinal se ries of teeth for attachment to a door insertible into the housing when the door is closed,

separate contacts within the housing for elec- 'trical connection to the car switch, a lever ''ulcrumed in the housing, means carried door upon failure ot' current, and cooperat-- ing meansupon the toothed member and the lever for eleetrically connecting the contacts positively when the toothed member is in-` serted into the housing and 'for automatically and positively breaking the connection between the contacts when the toothed member is withdrawn from the housing. i

` 6. The combination with a housing for installation at an elevator landing, and a tongue attachment to a door at an elevator landing, said tongue having a longitudinal series of teeth and being insertible into the housing when the door is shut and having a .slot, ot' a lever ;tulcrume-d in the housing, a

circut closing member mo-vably connected to the lever, contacts adjacent thereto adapted to be included in a. circut with the car switch of the elevator, a weight carried by the lever 'l'or holding said member normally spaced from the contacts, means carried by the weight for engagement by the slotted portion j of the tongue when inserted into the housing to shitt the lever positively and close the circut between the contacts, said. means cooperating positively to break the circut be-' tween the contacts when the tongue is withdrawn from the housing.

7. The combination with a housing for installation at an elevator landing, and a tongue attachment to a door at an elevator landing and having a longitudinal series o' teeth, said tongue being insertible into the housing when the door is shut and having a slot, of a lever fulcrumed in the housing, a. circut clos ing member movably connected to the lever, contacts adjacent thereto adapted to beincluded in a circut with the carswitch of the elevator, a weight carried by the lever tor holding said member normally spaced from the contacts, means carried by the weight for engagement by the slotted portion' 'of the tongue when inserted into the housing to shift the lever positively and close the circut between the contacts, said means cooperating positively to break the circut between the contacts when the tongue is withdrawn from the housing, a yieldingly controlled pawl for engaging the tongue to hold it in the housing when the door is partly or .entirely closed,

and'electrically operated means controlled by the making and breaking of the circuits to the contacts, for respeqtiVely holding the pawl in engegement with and 'eleasing it from the tongue.

8. The conbinution with an elevatocar, 21` motor for actuating the same, an enelosure, and a, door at the elevztolanding, of a` tongue movabie with the door and having a longitudiml series of teeth, a housing adjacont the landing for receiving the tongue when the door is closed, a pztwl within the housing 'o' engaging the teeth When the door is pa'tly 01' entirely closed, an eleet'oi'zgnet, means operated by the n'agnet when energized for holding the ptwi against disengagenent from the tongue said magnet being e'ectrically connected to the motor so :s to be energized dui-ing the operation of the motor,

pnilingthe seid switch to open position When the door is opened, and cooperating means upon the lock and ear for automatically releesing the tongue and pern'ittng the door to open when the motor is stopped and the inagnet is de-energized.

In testin'ony that I claim the foregoing as ny own, I have hereto` aflixed my signature.

MARTIN J. ROBERTSON. 

